//每个操作标识符对应的实际操作符号
var actionMap = {
    clear: ['clear'],
    minusSign: ['minusSign'],
    point: ['point'],
    divide: ['divide'],
    multiplication: ['multiplication'],
    subtraction: ['subtraction'],
    addition: ['addition'],
    dot: ['dot'],
    equal: ['equal']
}
var symbol = { "+": "+", "-": "-", "×": "*", "÷": "/", "%": "/100", "=": "=" };
